I have been using my Sekonic Zoom Master L-508 lightmeter in conjunction with my F3 since I got the camera last year. One of the things I really wanted to be able to nail down was getting the best exposure and consistent exposure for shoots where I may be limited in external tools, or need to shoot a light rig, or as it often happens there is just not enough time between setups and you want a quick “gauge” of what’s going on with your light. I’ve learned to be able to rely on this, trust it, and have it work for me.
I’m not going to suggest to anyone that you ONLY use a lightmeter in place of using your eye and some of the tools available on the F3, but for example using zebras to gauge exposure on skin can be extremely inaccurate because of the way light could be hitting the face. Are zebras just starting to appear on the bridge of the nose okay, or cheek, forehead… ? Just that difference alone can amount to one or more stops in adjustments and once you start moving your setup or subjects around you can really start to get inconsistencies I find.
If you watch the F3 exposure video on Abelcine’s website you can see that natively the F3 has an ISO of 800 at f4 to expose middle grey with a setting of 24fps, 1/48th shutter (or 180 degrees), 0db gain, and no ND filters engaged. As I been shooting in a variety of conditions under direct sun, overcast, indoors with controlled lighting, and outdoor snow conditions I have found that I can set my lightmeter to 24fps 180 degree shutter, take an f-stop reading and 9 times out of 10 it is accurate to my lens iris. As even with film, one has to obviously take into consideration what’s happening in the rest of the scene in terms or brightness or darkness and compensate accordingly.
So for example in this scene I walked through the trail to find the brightest patch of light coming through the trees. I measured f8 on my light meter and then set the built-in ND filter to “1” which is 1/8 ND (0.9) – reducing 3 stops from f8 to f2.8. Because there was lots of snow on the ground and in the trees I stopped down the iris an extra stop and set it to f4. Below is a frame grab from the scene,
A quick edit of clips from the unfinished promo video can be seen here,
During one take I did actually open the iris to f2.8 and it looked fine in the LCD but watching it later on a large screen the scene was semi-blown and the shot looked bad to me, so you have to use judgement with a lightmeter like with any tool. Had I only used zebras to show me when the snow started hitting 100 it would be debatable how much or little of the snow should show up in stripes, and worse at the expense of changing the exposure on my main scene elements (the actor and horse)!
Using a lightmeter is really no different than using a grey card so if you learn to use your meter with your camera you should easily know where 50 IRE is. From there you can compensate your iris accordingly depending on the color of skin you are shooting, look/style you are after, and lastly compensate for your overall scene if needed (primarily only for outdoors). One thing to be careful about as others have mentioned, is that when you start using the gamma curves you effectively start moving your middle grey point around which will skew things around. I find I can still pretty well match my iris f-stop to my lightmeter, then go through cinegamma 1,3 & 4 until I get the picture that looks the “best”. I avoid cinegamma 2 because it clips at 100 but if you need an immediate legal signal then cinegamma 2 is good.
Some examples using lightmeter:
f22 metered ambient*. 1 stop loss from overhead diffuser panel, 4 stops loss in ND filters, f4 on 85mm lens.
*This was metered away from the sun because subjects were more backlit. Typicially this works out to about 2 stops less then if metered against direct sun.